Microplastics have been found in tap water and bottled water. That naturally raises a practical question: Can you filter them out at home?
Yes. Household filtration can reduce plastic particles in drinking water. The important part is choosing a system with a real physical barrier, checking the exact model’s independent certification, and maintaining it on schedule.
For many households, reverse osmosis (RO) is the most comprehensive point-of-use option. It can provide a very fine membrane barrier for particles while also reducing many dissolved contaminants that an ordinary pitcher or carbon filter may leave behind.
That does not mean every RO system removes every microplastic or nanoplastic, or that every home needs RO. Here is how it works, what the evidence supports, and how to choose without relying on an oversized percentage printed on a product page.
What are microplastics, and are they in drinking water?
Microplastics are generally defined as plastic particles smaller than 5 millimeters. Nanoplastics are smaller still, often described as particles below 1 micrometer, although scientific definitions and testing methods are still developing.
Studies have reported plastic particles in both tap and bottled water. The exact numbers vary widely because researchers do not all measure the same size range or use the same laboratory methods. A study that can detect much smaller particles will usually report a much larger count.
The health questions are not fully settled. In its major drinking-water review, the World Health Organization concluded that the available evidence was limited and called for better, standardized research. That is a good reason for measured action, not panic. If reducing an avoidable source of plastic particles matters to your household, drinking water is a practical place to start.
Can you filter microplastics out of tap water?
Yes. Filters that include a sufficiently fine, well-maintained physical barrier can reduce microplastics.
A 2023 study of common point-of-use filters found that devices with microfiltration membranes removed substantially more plastic particles than a device relying on granular activated carbon and ion exchange alone. The study tested particles from 30 to 1,000 micrometers. It did not test residential RO systems or the smallest nanoplastics, but it reinforces a useful shopping rule: for particles, look for a verified membrane or a specific third-party microplastics reduction claim, not just carbon media and better-tasting water.
Municipal treatment also removes many particles before the water reaches your home. WHO has reported that optimized drinking-water and wastewater treatment can remove a large share of microplastics. Household filtration is an additional point-of-use step, not evidence that your utility is doing nothing.
What is reverse osmosis?
Reverse osmosis uses water pressure to move water across a selective membrane. The treated water passes to your drinking-water tap or carafe, while a separate stream carries concentrated material away.
Most home RO systems use several stages:
- A sediment prefilter catches larger debris that could foul the system.
- Activated carbon reduces chlorine and selected taste, odor, or organic compounds and helps protect the membrane.
- The RO membrane provides the main separation step.
- A postfilter polishes taste before the water reaches your glass.
- Some models add remineralization to change taste and pH after treatment.
You may see RO membranes described with a single “pore size.” That shorthand can be useful for comparison, but RO is not simply a kitchen sieve. Membrane chemistry, pressure, charge, molecular size, temperature, maintenance, and system design all affect performance.
Why RO is a strong option for microplastics
RO makes sense when you want more than a basic particle filter.
It provides a very fine physical barrier
Microplastics are particles. A sound RO membrane is designed to separate material at a much smaller scale than ordinary sediment or carbon-only filters.
It can address dissolved contaminants too
A certified RO system may also reduce specific dissolved contaminants such as arsenic, nitrate, fluoride, lead, or PFAS. The exact list varies by model. Never assume that “RO” or one certification badge covers every contaminant.
It is available in DIY formats
You do not need a whole-house system or professional installation to use RO for drinking water. Two practical formats are widely available:
- Countertop RO: Fill a feed tank, plug in the unit, and collect treated water in a reservoir or carafe. This is the simplest choice for renters or anyone who does not want to alter plumbing.
- Under-sink RO: Connect the system to the cold-water line and drain and install a dedicated faucet. Many homeowners can complete the installation themselves, although drilling a faucet hole may be the deciding factor.
Both formats treat water where you drink and cook with it, which is usually more economical than treating every gallon used for showers, laundry, and cleaning.
What RO does not guarantee
RO is strong technology, but the label alone is not proof of every claim.
NSF/ANSI 58 is not automatically a microplastics claim
NSF/ANSI 58 is the main standard for residential reverse-osmosis systems. It covers system safety and performance requirements, but each certified model carries only the reduction claims listed in its performance data sheet.
For a direct microplastics claim, look for the exact model in an accredited certifier’s directory with a microplastics reduction claim, commonly under NSF/ANSI 401. Do not rely on a brand-wide “NSF certified” badge without checking what it covers.
“Tested to NSF standards” is not the same as certification
An independent laboratory report can be useful evidence. It is still different from a current product certification that includes ongoing factory oversight and a public model listing. Look closely at phrases such as:
- certified by NSF, WQA, or IAPMO;
- certified to NSF/ANSI 58 for a named claim;
- independently tested against NSF/ANSI 58;
- uses an NSF-certified component.
Those statements do not mean the same thing.
A TDS meter does not measure microplastics
Some RO systems display total dissolved solids. That reading can help show that the membrane is reducing dissolved ions, but it does not count plastic particles and cannot prove that water is free of microplastics.
Maintenance still matters
A neglected system is not the system described on the certification sheet. Replace filters on schedule, sanitize or descale as directed, check for leaks, and stop using the unit if performance changes unexpectedly.
Reverse osmosis vs. other ways to reduce microplastics
RO is not the only reasonable option. The right choice depends on what else is in your water, your budget, your space, and how much maintenance you will actually do.
Microfiltration and ultrafiltration
A certified fine-membrane filter can be a strong option when plastic particles are the main concern. These systems usually preserve dissolved minerals, often use no electricity, and do not create an RO reject stream.
The trade-off is narrower treatment. A membrane designed to stop particles may not reduce dissolved contaminants such as nitrate, fluoride, or arsenic. It also should not be assumed to capture particles below its verified range.
Best for: households with treated municipal water that want particle reduction with simpler operation and less wastewater.
A filter certified specifically for microplastics
Some non-RO products carry an NSF/ANSI 401 microplastics reduction claim. This can be more meaningful for the narrow question of microplastics than a generic RO badge with no model-specific microplastics claim.
Check what else the model reduces. A filter can be well verified for microplastics but still offer a narrower contaminant list than RO.
Best for: readers who want a direct certified microplastics claim without full RO treatment.
Activated carbon
Activated carbon is useful for chlorine, taste and odor, and certain organic contaminants. It is often an important prefilter or postfilter in a complete system.
Carbon alone is not our first choice for microplastics unless the product also includes a fine physical barrier or a specific certified microplastics claim. In the 2023 point-of-use study, the carbon/ion-exchange-only device did not perform like the membrane-equipped filters.
Best for: taste, odor, and model-specific chemical claims, not as a stand-alone assumption about every particle size.
Distillation
Distillation boils water and condenses the vapor into a separate container. Nonvolatile particles, including plastic particles, should remain behind.
It can be effective, but it is slow, uses energy, and requires regular scale cleaning. Volatile compounds may need additional treatment, which is why some distillers include a carbon stage.
Best for: households willing to trade speed and energy use for a different physical separation method.
Boiling and filtering hard water
A 2024 laboratory study found that boiling mineral-rich hard water could trap many nano- and microplastic particles in calcium carbonate scale. The result depended on water hardness and also required separating the scale afterward.
This is interesting evidence, but it is not a universal replacement for a certified home filter. Soft water will not behave the same way, and simply boiling without a separation step does not remove what remains in the pot.
Best for: a research-backed household technique in the right water conditions, but it is not our primary everyday recommendation.
The trade-offs of RO
Reject water
RO separates water into a treated stream and a concentrate stream. Efficiency varies widely by model and water conditions. Compare the certified or documented recovery ratio, not just marketing language.
Countertop units may recirculate concentrate in the feed tank. A high “pure-to-drain” ratio can still leave a concentrated portion that you empty later. Under-sink systems send reject water directly to the drain.
If practical, reject water from a removable countertop tank can be used for nonfood tasks such as cleaning. Follow the manufacturer’s directions, and do not store it for drinking or cooking.
Cost and ongoing filters
The purchase price is only part of the cost. Compare:
- replacement-filter price and frequency;
- annual cost at your household’s usage;
- warranty and return shipping;
- sanitizing or descaling supplies;
- replacement membrane availability;
- electricity use for powered units.
Space and installation
Countertop units take work-surface space and need a nearby outlet. Under-sink systems preserve the counter but need cabinet space, plumbing access, a drain connection, and usually a dedicated faucet.
Minerals and taste
RO reduces dissolved minerals along with unwanted dissolved contaminants. Some people prefer the taste after a remineralization stage. Remineralization is an optional taste feature, not a medical treatment or a guarantee of health benefits.
How to choose a system
Use this checklist before buying:
- Read your local water report. Public water utilities publish a Consumer Confidence Report. Private wells need periodic laboratory testing.
- Decide what you want to reduce. Microplastics may be one concern among lead, arsenic, nitrate, PFAS, chlorine, or hardness.
- Search the exact model in a live directory. Check NSF, WQA, or IAPMO, not only the manufacturer’s logo.
- Read the performance data sheet. Confirm every contaminant claim you care about.
- Look for a specific microplastics claim. NSF/ANSI 401 is the key standard to look for; confirm the model and claim.
- Match the format to your home. Choose countertop for no plumbing changes or under-sink for higher on-demand capacity and a clear counter.
- Calculate annual maintenance. A less expensive machine with proprietary filters can cost more over time.
- Check the water-contact path. No RO unit is literally plastic-free. If minimizing plastic contact is part of your goal, compare feed tanks, tubing, internal reservoirs, carafes, faucets, and how long treated water sits in plastic.
- Check efficiency and support. Review reject-water ratio, warranty, replacement parts, and US-based service.
- Replace filters on time. A well-chosen system only works as designed when it is maintained.
RO options we are researching
Disclosure: Some links in this section may become affiliate links. If you buy through an affiliate link, Plastic Free Kitchen may earn a commission at no additional cost to you. We only include products that fit the article and will identify any product sold directly by us.
AquaTru: the strongest current certified-microplastics option
AquaTru sells countertop and under-sink RO systems. Its current product materials identify an IAPMO-certified microplastics reduction claim, and the product line includes a countertop model with a glass carafe.
- AquaTru Carafe: compact countertop format with a glass serving carafe; no plumbing required.
- AquaTru Classic: larger countertop format for households that need more capacity.
- AquaTru Under Sink: a DIY-capable option that keeps the main unit out of sight.
Explore AquaTru reverse-osmosis systems
Waterdrop G3P600: a modern tankless under-sink candidate
The Waterdrop G3P600 is a compact, 600-gallon-per-day tankless RO system designed for DIY under-sink installation. The exact model is listed for NSF/ANSI 58 TDS reduction and NSF/ANSI/CAN 372 lead-content compliance.
That certification should not be expanded into a specific certified microplastics percentage. We view the G3P600 as a strong broad RO candidate, while AquaTru currently has the clearer model-level microplastics claim.
A lower-waste, non-RO option
If your main goal is a certified microplastics reduction claim rather than broad dissolved-contaminant treatment, a certified microfiltration or carbon-plus-membrane system may be enough. Selected Aquasana countertop and under-sink filters are marketed with a specific certified microplastics reduction claim.
Explore Aquasana under-sink filters
Before buying any of these, verify the current exact-model certification and performance data sheet. Product names, prices, formulations, and certifications can change.
The bottom line
You can reduce microplastics in drinking water at home. The most dependable approach is to choose a well-maintained system with a verified physical barrier and an exact, third-party-certified performance claim.
Reverse osmosis is our best all-around choice when you also want broad reduction of specified dissolved contaminants. If microplastics are the only concern, a certified micro- or ultrafiltration system (or another filter with a specific NSF/ANSI 401 microplastics claim) may be simpler and use less water.
Start with your local water report. Then buy for the contaminants you actually have, verify the exact model, and keep up with maintenance. That is more useful than chasing the largest percentage on the box.
Frequently asked questions
Does reverse osmosis remove microplastics?
A properly functioning RO membrane provides a very fine physical barrier and is one of the strongest household technologies for reducing plastic particles. For the most defensible product claim, choose an exact model with third-party certification for microplastics reduction rather than assuming every RO unit has been tested for every particle size.
Does reverse osmosis remove nanoplastics?
RO is expected to reject particles at very small scales, but direct, standardized testing of residential units across the full nanoplastic size range is still limited. Avoid universal “100% removal” claims, especially when a product does not disclose the tested sizes and method.
Will a carbon pitcher filter remove microplastics?
Some will, but not because every carbon filter does. Look for a fine physical membrane or a specific NSF/ANSI 401 microplastics reduction claim on the exact filter model.
What certification should I look for?
For RO, start with NSF/ANSI 58 and read the model’s exact reduction claims. For a direct microplastics claim, look for the exact model under NSF/ANSI 401 in an accredited certifier’s live directory.
Is countertop or under-sink RO better?
Countertop RO is easier to set up and works well for renters. Under-sink RO preserves counter space and usually provides faster, on-demand water, but it requires plumbing connections and a dedicated faucet.
Does boiling water remove microplastics?
One 2024 study found that boiling hard water could trap many particles in mineral scale, especially in harder water. The scale still had to be separated, and the result does not apply equally to soft water. Boiling alone is not our primary recommendation.
Is bottled water a better alternative?
Not necessarily. Studies have also found micro- and nanoplastics in bottled water, and plastic packaging can be another source. A well-chosen home filter paired with a reusable glass or stainless-steel bottle is a more practical long-term approach for many households.
Sources
- World Health Organization, Microplastics in drinking-water (2019): https://www.who.int/publications/i/item/9789241516198
- WHO, “WHO calls for more research into microplastics and a crackdown on plastic pollution” (2019): https://www.who.int/news/item/22-08-2019-who-calls-for-more-research-into-microplastics-and-a-crackdown-on-plastic-pollution
- Cherian et al., “Microplastic Removal from Drinking Water Using Point-of-Use Devices,” Polymers 15(6), 1331 (2023): https://pmc.ncbi.nlm.nih.gov/articles/PMC10054062/
- Zhang et al., “Removal Efficiency of Micro- and Nanoplastics (180 nm–125 μm) During Drinking Water Treatment,” Science of the Total Environment 720, 137383 (2020): https://pmc.ncbi.nlm.nih.gov/articles/PMC7241221/
- Zeng et al., “Drinking Boiled Tap Water Reduces Human Intake of Nanoplastics and Microplastics,” Environmental Science & Technology Letters (2024): https://doi.org/10.1021/acs.estlett.4c00081
- NSF, “Water Filters FAQs”: https://www.nsf.org/about-nsf/faqs/water-filters-faqs
- NSF, residential water-treatment standards overview: https://www.nsf.org/consumer-resources/articles/standards-water-treatment-systems